The present invention relates to a magnetic disk apparatus and, more particularly, relates to a magnetic disk apparatus having a large storage capacity.
In a magnetic disk apparatus used as an external memory for a computer, a magnetic head floating on a recording face of the magnetic disk with a predetermined gap left therebetween operates for recording and reproducing an objective information on the magnetic disk through magnetic flux.
Accordingly, in order to attain and realize a large capacity construction of the magnetic disk apparatus, it is of importance that a recording density of the magnetic information on the magnetic disk is enhanced, and that the magnetic disk is packaged with as many disks as possible within the apparatus housing case, which is limited in size in accordance with various restrictions.
The recording density of magnetic disks has been enhanced in recent years, which is the result of an improvement in magnetic materials constituting the magnetic disk, an improvement in the high frequency characteristics of magnetic heads for recording magnetic information on the magnetic disk and so forth.
The recording density of magnetic information on a magnetic disk and a floating gap of the magnetic head are related in inverse proportion. A standard minimum floating gap is 0.2 .mu.m or so today. Thus, the stability of the floating gap must be accurately maintained from the viewpoint of realizing a large capacity construction and high reliability of the magnetic disk apparatus.
A desired floating gap is obtained for the magnetic head by balancing a dynamic lift of an air viscous flow generated from the rotation of the magnetic disk and a pressure force created by a leaf spring or the like packaged with the head arm. Accordingly, the aforementioned dynamic lift and pressure must be controlled with high precision so as to accurately maintain the floating gap. The dynamic lift can be set precisely by keeping the width of the magnetic heads and the rotational frequency of the magnetic disk constant with high accuracy. The pressure can be controlled by keeping a spring constant of the leaf spring uniform and by precisely maintaining the relative position between the magnetic disk and the magnetic head.
The situation being such as mentioned, the cardinal point for realizing a large capacity construction of a magnetic disk apparatus lies in packaging a multiplicity of magnetic disks within a housing case limited in size, and placing the magnetic disk and the magnetic head in precise relative position at the time of assembling the apparatus.
The prior art, for example in U.S. Pat. No. 4,669,004, concerns a conventional magnetic disk apparatus as one of known construction having therein magnetic disks. In Japanese Laid-Open patent 63-53770, the art disclosed refers to the head arm structure.